Abstracto

Photocatalytic Study of Two Azo Dye Derivatives, Ponceau Bs and Reactive Blue 160 in Aqueous Suspension of TiO2: Adsorption Isotherm and Decolorization Kinetics

Niyaz A. Mir, A. Khan, A. A. Dar and M. Muneer

This paper deals with the photocatalyzed decolorization kinetics of two azo dye derivatives, Ponceau BS and Reactive Blue 160 under a variety of conditions in aqueous suspension of TiO2 using UV light. The efficiency of different TiO2 photocatalysts such as PC500-Milennium, UV100-Hombikat and P25-Degussa were compared for the decolorization of both dyes. Photocatalytic, photolytic, and adsorption experiments were performed, showing that adsorption of both dyes on TiO2-UV100 is appreciable compared to that on P25 and favorable by the Langmuir approach. The effects of various parameters such as catalyst loading, initial pH, substrate concentration and electron acceptors such as H2O2, KBrO3 on the decolorization have been investigated. Under the operating conditions of this study, the photocatalytic decolorization of dyes under study followed pseudo first-order kinetics. The photo decolorization kinetics was discussed in terms of Langmuir-Hinshelwood kinetic model. The decolorization efficiency was found to be efficient in acidic medium which gradually slowed down in the alkaline medium due to the effect of charge repulsion.